Background/Rationale: Across VA?despite the availability of numerous evidence-based housing interventions?many homeless Veterans still struggle to obtain and sustain housing. Social skills (interpersonal communication or instrumental skills, like money management) are an important?but underappreciated? determinant of housing outcomes for homeless adults. However, social skills interventions are usually absent from the array of VA homeless services. Objectives: This CDA will prepare me to become a VA implementation scientist focused on vulnerable populations, particularly homeless-experienced Veterans; it will develop and study the implementation and effectiveness of a ?skills intervention??built from existing, effective social skills interventions and focused on housing-related social skills?tailored to the VA Supportive Housing (VASH) program. This intervention will be co-delivered by a consumer provider (?peer?) and a licensed clinical social worker, aiming to improve VASH participants' housing retention and mental health. Using the theoretical framework of the Behavioral Model for Vulnerable Populations, with additional guidance from the Consolidated Framework for Implementation Research (CFIR), the Specific Aims are to: 1) develop a skills intervention that improves housing retention and mental health among homeless-experienced Veterans; 2) in a controlled pilot trial, study the feasibility, acceptability, and effectiveness of the skills intervention on factors strongly associated with improved housing retention and mental health among homeless-experienced Veterans, including enabling factors (social skills, cognition) and behaviors (health service use, social interactions, money management); and 3) examine barriers to and facilitators of future implementation of the skills intervention in routine VASH care. Methods: To achieve Specific Aim 1, we will complement our ongoing literature review of social skills training interventions by conducting key informant interviews; we will also use the RAND/UCLA appropriateness method to convene an expert panel of local and national homeless program stakeholders (Veteran consumer providers, VA staff, and leadership). Specific Aims 2 and 3 entail a controlled pilot trial of the intervention that employs an effectiveness-implementation hybrid type 1 design. For Specific Aim 2, we will implement the skills intervention within two VA Greater Los Angeles (GLA) VASH teams. We will assess its feasibility and acceptability, also comparing changes (from baseline to 6-month follow-up) in social skills, service use, social interactions, and money management among Veterans who receive the intervention (n=30) vs. a control group (n=20) of Veterans on distinct GLA VASH teams receiving usual care. For Specific Aim 3, we will use surveys and qualitative methods to explore potential barriers to and facilitators of future implementation of the intervention in routine care. The CDA training component will focus on implementation science, qualitative and quantitative methods, pragmatic trials, and skills to facilitate academic pursuits. Significance: Though the VA has dramatically expanded its use of evidence-based practices for homeless Veterans, there remain substantial challenges to keeping homeless-experienced Veterans housed and ensuring their health and well-being. To accelerate VA's efforts to improve care for homeless Veterans, we must implement novel services that are effective in other VA settings but have not been implemented within homeless services. Moreover, as a junior physician-investigator committed to improving care for homeless Veterans, I must fill gaps in my training, primarily in the areas of implementation science and qualitative methods.